Listen before talk procedure in a wireless device and wireless network

ABSTRACT

A wireless device receives an uplink grant for a licensed assisted access (LAA) cell. The uplink grant comprises a physical uplink shared channel (PUSCH) starting position field and a listen-before-talk (LBT) type field. The PUSCH starting position field indicates a PUSCH starting position in a subframe of the LAA cell. The LBT type field indicates at least one of a first LBT type or a second LBT type for the subframe. A determination is made based, at least, on uplink transmissions by the wireless device in a preceding adjacent subframe of the LAA cell, to: perform an LBT procedure for transmission of uplink signals in the subframe, or transmit the uplink signals without performing the LBT procedure for the subframe, regardless of the LBT type field indicating the first LBT type or the second LBT type. The uplink signals in the subframe may be transmitted via the LAA cell.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/348,869, filed Jun. 11, 2016, which is hereby incorporated byreference in their entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present disclosureare described herein with reference to the drawings.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers in a carrier group as per an aspect of anembodiment of the present disclosure.

FIG. 3 is an example diagram depicting OFDM radio resources as per anaspect of an embodiment of the present disclosure.

FIG. 4 is an example block diagram of a base station and a wirelessdevice as per an aspect of an embodiment of the present disclosure.

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure.

FIG. 6 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 7 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure.

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure.

FIG. 10 is an example diagram depicting a downlink burst as per anaspect of an embodiment of the present disclosure.

FIG. 11 is an example diagram depicting a plurality of cells as per anaspect of an embodiment of the present disclosure.

FIG. 12 is an example diagram depicting listen before talk procedures asper an aspect of an embodiment of the present disclosure.

FIG. 13 is an example diagram depicting listen before talk procedures asper an aspect of an embodiment of the present disclosure.

FIG. 14 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present disclosure enable operation ofcarrier aggregation. Embodiments of the technology disclosed herein maybe employed in the technical field of multicarrier communicationsystems.

The following Acronyms are used throughout the present disclosure:

ASIC application-specific integrated circuit

BPSK binary phase shift keying

CA carrier aggregation

CSI channel state information

CDMA code division multiple access

CSS common search space

CPLD complex programmable logic devices

CC component carrier

DL downlink

DCI downlink control information

DC dual connectivity

EPC evolved packet core

E-UTRAN evolved-universal terrestrial radio access network

FPGA field programmable gate arrays

FDD frequency division multiplexing

HDL hardware description languages

HARQ hybrid automatic repeat request

IE information element

LAA licensed assisted access

LTE long term evolution

MCG master cell group

MeNB master evolved node B

MIB master information block

MAC media access control

MAC media access control

MME mobility management entity

NAS non-access stratum

OFDM orthogonal frequency division multiplexing

PDCP packet data convergence protocol

PDU packet data unit

PHY physical

PDCCH physical downlink control channel

PHICH physical HARQ indicator channel

PUCCH physical uplink control channel

PUSCH physical uplink shared channel

PCell primary cell

PCell primary cell

PCC primary component carrier

PSCell primary secondary cell

pTAG primary timing advance group

QAM quadrature amplitude modulation

QPSK quadrature phase shift keying

RBG Resource Block Groups

RLC radio link control

RRC radio resource control

RA random access

RB resource blocks

SCC secondary component carrier

SCell secondary cell

Scell secondary cells

SCG secondary cell group

SeNB secondary evolved node B

sTAGs secondary timing advance group

SDU service data unit

S-GW serving gateway

SRB signaling radio bearer

SC-OFDM single carrier-OFDM

SFN system frame number

SIB system information block

TAI tracking area identifier

TAT time alignment timer

TDD time division duplexing

TDMA time division multiple access

TA timing advance

TAG timing advance group

TB transport block

UL uplink

UE user equipment

VHDL VHSIC hardware description language

Example embodiments of the disclosure may be implemented using variousphysical layer modulation and transmission mechanisms. Exampletransmission mechanisms may include, but are not limited to: CDMA, OFDM,TDMA, Wavelet technologies, and/or the like. Hybrid transmissionmechanisms such as TDMA/CDMA, and OFDM/CDMA may also be employed.Various modulation schemes may be applied for signal transmission in thephysical layer. Examples of modulation schemes include, but are notlimited to: phase, amplitude, code, a combination of these, and/or thelike. An example radio transmission method may implement QAM using BPSK,QPSK, 16-QAM, 64-QAM, 256-QAM, and/or the like. Physical radiotransmission may be enhanced by dynamically or semi-dynamically changingthe modulation and coding scheme depending on transmission requirementsand radio conditions.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure. As illustrated inthis example, arrow(s) in the diagram may depict a subcarrier in amulticarrier OFDM system. The OFDM system may use technology such asOFDM technology, DFTS-OFDM, SC-OFDM technology, or the like. Forexample, arrow 101 shows a subcarrier transmitting information symbols.FIG. 1 is for illustration purposes, and a typical multicarrier OFDMsystem may include more subcarriers in a carrier. For example, thenumber of subcarriers in a carrier may be in the range of 10 to 10,000subcarriers. FIG. 1 shows two guard bands 106 and 107 in a transmissionband. As illustrated in FIG. 1, guard band 106 is between subcarriers103 and subcarriers 104. The example set of subcarriers A 102 includessubcarriers 103 and subcarriers 104. FIG. 1 also illustrates an exampleset of subcarriers B 105. As illustrated, there is no guard band betweenany two subcarriers in the example set of subcarriers B 105. Carriers ina multicarrier OFDM communication system may be contiguous carriers,non-contiguous carriers, or a combination of both contiguous andnon-contiguous carriers.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentdisclosure. A multicarrier OFDM communication system may include one ormore carriers, for example, ranging from 1 to 10 carriers. Carrier A 204and carrier B 205 may have the same or different timing structures.Although FIG. 2 shows two synchronized carriers, carrier A 204 andcarrier B 205 may or may not be synchronized with each other. Differentradio frame structures may be supported for FDD and TDD duplexmechanisms. FIG. 2 shows an example FDD frame timing. Downlink anduplink transmissions may be organized into radio frames 201. In thisexample, the radio frame duration is 10 msec. Other frame durations, forexample, in the range of 1 to 100 msec may also be supported. In thisexample, each 10 ms radio frame 201 may be divided into ten equallysized subframes 202. Other subframe durations such as 0.5 msec, 1 msec,2 msec, and 5 msec may also be supported. Subframe(s) may consist of twoor more slots (for example, slots 206 and 207). For the example of FDD,10 subframes may be available for downlink transmission and 10 subframesmay be available for uplink transmissions in each 10 ms interval. Uplinkand downlink transmissions may be separated in the frequency domain.Slot(s) may include a plurality of OFDM symbols 203. The number of OFDMsymbols 203 in a slot 206 may depend on the cyclic prefix length andsubcarrier spacing.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present disclosure. The resource grid structure intime 304 and frequency 305 is illustrated in FIG. 3. The quantity ofdownlink subcarriers or RBs (in this example 6 to 100 RBs) may depend,at least in part, on the downlink transmission bandwidth 306 configuredin the cell. The smallest radio resource unit may be called a resourceelement (e.g. 301). Resource elements may be grouped into resourceblocks (e.g. 302). Resource blocks may be grouped into larger radioresources called Resource Block Groups (RBG) (e.g. 303). The transmittedsignal in slot 206 may be described by one or several resource grids ofa plurality of subcarriers and a plurality of OFDM symbols. Resourceblocks may be used to describe the mapping of certain physical channelsto resource elements. Other pre-defined groupings of physical resourceelements may be implemented in the system depending on the radiotechnology. For example, 24 subcarriers may be grouped as a radio blockfor a duration of 5 msec. In an illustrative example, a resource blockmay correspond to one slot in the time domain and 180 kHz in thefrequency domain (for 15 KHz subcarrier bandwidth and 12 subcarriers).

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure. FIG. 5A shows an example uplink physicalchannel. The baseband signal representing the physical uplink sharedchannel may perform the following processes. These functions areillustrated as examples and it is anticipated that other mechanisms maybe implemented in various embodiments. The functions may comprisescrambling, modulation of scrambled bits to generate complex-valuedsymbols, mapping of the complex-valued modulation symbols onto one orseveral transmission layers, transform precoding to generatecomplex-valued symbols, precoding of the complex-valued symbols, mappingof precoded complex-valued symbols to resource elements, generation ofcomplex-valued time-domain DFTS-OFDM/SC-FDMA signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued DFTS-OFDM/SC-FDMA baseband signal for each antenna portand/or the complex-valued PRACH baseband signal is shown in FIG. 5B.Filtering may be employed prior to transmission.

An example structure for Downlink Transmissions is shown in FIG. 5C. Thebaseband signal representing a downlink physical channel may perform thefollowing processes. These functions are illustrated as examples and itis anticipated that other mechanisms may be implemented in variousembodiments. The functions include scrambling of coded bits in each ofthe codewords to be transmitted on a physical channel; modulation ofscrambled bits to generate complex-valued modulation symbols; mapping ofthe complex-valued modulation symbols onto one or several transmissionlayers; precoding of the complex-valued modulation symbols on each layerfor transmission on the antenna ports; mapping of complex-valuedmodulation symbols for each antenna port to resource elements;generation of complex-valued time-domain OFDM signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued OFDM baseband signal for each antenna port is shown inFIG. 5D. Filtering may be employed prior to transmission.

FIG. 4 is an example block diagram of a base station 401 and a wirelessdevice 406, as per an aspect of an embodiment of the present disclosure.A communication network 400 may include at least one base station 401and at least one wireless device 406. The base station 401 may includeat least one communication interface 402, at least one processor 403,and at least one set of program code instructions 405 stored innon-transitory memory 404 and executable by the at least one processor403. The wireless device 406 may include at least one communicationinterface 407, at least one processor 408, and at least one set ofprogram code instructions 410 stored in non-transitory memory 409 andexecutable by the at least one processor 408. Communication interface402 in base station 401 may be configured to engage in communicationwith communication interface 407 in wireless device 406 via acommunication path that includes at least one wireless link 411.Wireless link 411 may be a bi-directional link. Communication interface407 in wireless device 406 may also be configured to engage in acommunication with communication interface 402 in base station 401. Basestation 401 and wireless device 406 may be configured to send andreceive data over wireless link 411 using multiple frequency carriers.According to aspects of an embodiments, transceiver(s) may be employed.A transceiver is a device that includes both a transmitter and receiver.Transceivers may be employed in devices such as wireless devices, basestations, relay nodes, and/or the like. Example embodiments for radiotechnology implemented in communication interface 402, 407 and wirelesslink 411 are illustrated are FIG. 1, FIG. 2, FIG. 3, FIG. 5, andassociated text.

An interface may be a hardware interface, a firmware interface, asoftware interface, and/or a combination thereof. The hardware interfacemay include connectors, wires, electronic devices such as drivers,amplifiers, and/or the like. A software interface may include codestored in a memory device to implement protocol(s), protocol layers,communication drivers, device drivers, combinations thereof, and/or thelike. A firmware interface may include a combination of embeddedhardware and code stored in and/or in communication with a memory deviceto implement connections, electronic device operations, protocol(s),protocol layers, communication drivers, device drivers, hardwareoperations, combinations thereof, and/or the like.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics inthe device, whether the device is in an operational or non-operationalstate.

According to various aspects of an embodiment, an LTE network mayinclude a multitude of base stations, providing a user planePDCP/RLC/MAC/PHY and control plane (RRC) protocol terminations towardsthe wireless device. The base station(s) may be interconnected withother base station(s) (for example, interconnected employing an X2interface). Base stations may also be connected employing, for example,an S1 interface to an EPC. For example, base stations may beinterconnected to the MME employing the S1-MME interface and to the S-G)employing the S1-U interface. The S1 interface may support amany-to-many relation between MMEs/Serving Gateways and base stations. Abase station may include many sectors for example: 1, 2, 3, 4, or 6sectors. A base station may include many cells, for example, rangingfrom 1 to 50 cells or more. A cell may be categorized, for example, as aprimary cell or secondary cell. At RRC connectionestablishment/re-establishment/handover, one serving cell may providethe NAS (non-access stratum) mobility information (e.g. TAI), and at RRCconnection re-establishment/handover, one serving cell may provide thesecurity input. This cell may be referred to as the Primary Cell(PCell). In the downlink, the carrier corresponding to the PCell may bethe Downlink Primary Component Carrier (DL PCC), while in the uplink,the carrier corresponding to the PCell may be the Uplink PrimaryComponent Carrier (UL PCC). Depending on wireless device capabilities,Secondary Cells (SCells) may be configured to form together with thePCell a set of serving cells. In the downlink, the carrier correspondingto an SCell may be a Downlink Secondary Component Carrier (DL SCC),while in the uplink, it may be an Uplink Secondary Component Carrier (ULSCC). An SCell may or may not have an uplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,may be assigned a physical cell ID and a cell index. A carrier (downlinkor uplink) may belong to only one cell. The cell ID or Cell index mayalso identify the downlink carrier or uplink carrier of the cell(depending on the context it is used). In the specification, cell ID maybe equally referred to a carrier ID, and cell index may be referred tocarrier index. In implementation, the physical cell ID or cell index maybe assigned to a cell. A cell ID may be determined using asynchronization signal transmitted on a downlink carrier. A cell indexmay be determined using RRC messages. For example, when thespecification refers to a first physical cell ID for a first downlinkcarrier, the specification may mean the first physical cell ID is for acell comprising the first downlink carrier. The same concept may apply,for example, to carrier activation. When the specification indicatesthat a first carrier is activated, the specification may also mean thatthe cell comprising the first carrier is activated.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in a wireless device, a base station, a radio environment, a network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, traffic load, initial systemset up, packet sizes, traffic characteristics, a combination of theabove, and/or the like. When the one or more criteria are met, variousexample embodiments may be applied. Therefore, it may be possible toimplement example embodiments that selectively implement disclosedprotocols.

A base station may communicate with a mix of wireless devices. Wirelessdevices may support multiple technologies, and/or multiple releases ofthe same technology. Wireless devices may have some specificcapability(ies) depending on its wireless device category and/orcapability(ies). A base station may comprise multiple sectors. When thisdisclosure refers to a base station communicating with a plurality ofwireless devices, this disclosure may refer to a subset of the totalwireless devices in a coverage area. This disclosure may refer to, forexample, a plurality of wireless devices of a given LTE release with agiven capability and in a given sector of the base station. Theplurality of wireless devices in this disclosure may refer to a selectedplurality of wireless devices, and/or a subset of total wireless devicesin a coverage area which perform according to disclosed methods, and/orthe like. There may be a plurality of wireless devices in a coveragearea that may not comply with the disclosed methods, for example,because those wireless devices perform based on older releases of LTEtechnology.

FIG. 6 and FIG. 7 are example diagrams for protocol structure with CAand DC as per an aspect of an embodiment of the present disclosure.E-UTRAN may support Dual Connectivity (DC) operation whereby a multipleRX/TX UE in RRC_CONNECTED may be configured to utilize radio resourcesprovided by two schedulers located in two eNBs connected via a non-idealbackhaul over the X2 interface. eNBs involved in DC for a certain UE mayassume two different roles: an eNB may either act as an MeNB or as anSeNB. In DC a UE may be connected to one MeNB and one SeNB. Mechanismsimplemented in DC may be extended to cover more than two eNBs. FIG. 7illustrates one example structure for the UE side MAC entities when aMaster Cell Group (MCG) and a Secondary Cell Group (SCG) are configured,and it may not restrict implementation. Media Broadcast MulticastService (MBMS) reception is not shown in this figure for simplicity.

In DC, the radio protocol architecture that a particular bearer uses maydepend on how the bearer is setup. Three alternatives may exist, an MCGbearer, an SCG bearer and a split bearer as shown in FIG. 6. RRC may belocated in MeNB and SRBs may be configured as a MCG bearer type and mayuse the radio resources of the MeNB. DC may also be described as havingat least one bearer configured to use radio resources provided by theSeNB. DC may or may not be configured/implemented in example embodimentsof the disclosure.

In the case of DC, the UE may be configured with two MAC entities: oneMAC entity for MeNB, and one MAC entity for SeNB. In DC, the configuredset of serving cells for a UE may comprise two subsets: the Master CellGroup (MCG) containing the serving cells of the MeNB, and the SecondaryCell Group (SCG) containing the serving cells of the SeNB. For a SCG,one or more of the following may be applied. At least one cell in theSCG may have a configured UL CC and one of them, named PSCell (or PCellof SCG, or sometimes called PCell), may be configured with PUCCHresources. When the SCG is configured, there may be at least one SCGbearer or one Split bearer. Upon detection of a physical layer problemor a random access problem on a PSCell, or the maximum number of RLCretransmissions has been reached associated with the SCG, or upondetection of an access problem on a PSCell during a SCG addition or aSCG change: a RRC connection re-establishment procedure may not betriggered, UL transmissions towards cells of the SCG may be stopped, anda MeNB may be informed by the UE of a SCG failure type. For splitbearer, the DL data transfer over the MeNB may be maintained. The RLC AMbearer may be configured for the split bearer. Like a PCell, a PSCellmay not be de-activated. A PSCell may be changed with a SCG change (forexample, with a security key change and a RACH procedure), and/orneither a direct bearer type change between a Split bearer and a SCGbearer nor simultaneous configuration of a SCG and a Split bearer may besupported.

With respect to the interaction between a MeNB and a SeNB, one or moreof the following principles may be applied. The MeNB may maintain theRRM measurement configuration of the UE and may, (for example, based onreceived measurement reports or traffic conditions or bearer types),decide to ask a SeNB to provide additional resources (serving cells) fora UE. Upon receiving a request from the MeNB, a SeNB may create acontainer that may result in the configuration of additional servingcells for the UE (or decide that it has no resource available to do so).For UE capability coordination, the MeNB may provide (part of) the ASconfiguration and the UE capabilities to the SeNB. The MeNB and the SeNBmay exchange information about a UE configuration by employing RRCcontainers (inter-node messages) carried in X2 messages. The SeNB mayinitiate a reconfiguration of its existing serving cells (for example, aPUCCH towards the SeNB). The SeNB may decide which cell is the PSCellwithin the SCG. The MeNB may not change the content of the RRCconfiguration provided by the SeNB. In the case of a SCG addition and aSCG SCell addition, the MeNB may provide the latest measurement resultsfor the SCG cell(s). Both a MeNB and a SeNB may know the SFN andsubframe offset of each other by OAM, (for example, for the purpose ofDRX alignment and identification of a measurement gap). In an example,when adding a new SCG SCell, dedicated RRC signaling may be used forsending required system information of the cell as for CA, except forthe SFN acquired from a MIB of the PSCell of a SCG.

In an example, serving cells may be grouped in a TA group (TAG). Servingcells in one TAG may use the same timing reference. For a given TAG,user equipment (UE) may use at least one downlink carrier as a timingreference. For a given TAG, a UE may synchronize uplink subframe andframe transmission timing of uplink carriers belonging to the same TAG.In an example, serving cells having an uplink to which the same TAapplies may correspond to serving cells hosted by the same receiver. AUE supporting multiple TAs may support two or more TA groups. One TAgroup may contain the PCell and may be called a primary TAG (pTAG). In amultiple TAG configuration, at least one TA group may not contain thePCell and may be called a secondary TAG (sTAG). In an example, carrierswithin the same TA group may use the same TA value and/or the sametiming reference. When DC is configured, cells belonging to a cell group(MCG or SCG) may be grouped into multiple TAGs including a pTAG and oneor more sTAGs.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure. In Example 1, pTAG comprises aPCell, and an sTAG comprises SCell1. In Example 2, a pTAG comprises aPCell and SCell1, and an sTAG comprises SCell2 and SCell3. In Example 3,pTAG comprises PCell and SCell1, and an sTAG1 includes SCell2 andSCell3, and sTAG2 comprises SCell4. Up to four TAGs may be supported ina cell group (MCG or SCG) and other example TAG configurations may alsobe provided. In various examples in this disclosure, example mechanismsare described for a pTAG and an sTAG. Some of the example mechanisms maybe applied to configurations with multiple sTAGs.

In an example, an eNB may initiate an RA procedure via a PDCCH order foran activated SCell. This PDCCH order may be sent on a scheduling cell ofthis SCell. When cross carrier scheduling is configured for a cell, thescheduling cell may be different than the cell that is employed forpreamble transmission, and the PDCCH order may include an SCell index.At least a non-contention based RA procedure may be supported forSCell(s) assigned to sTAG(s).

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure. An eNB transmits an activation command 600 to activate anSCell. A preamble 602 (Msg1) may be sent by a UE in response to a PDCCHorder 601 on an SCell belonging to an sTAG. In an example embodiment,preamble transmission for SCells may be controlled by the network usingPDCCH format 1A. Msg2 message 603 (RAR: random access response) inresponse to the preamble transmission on the SCell may be addressed toRA-RNTI in a PCell common search space (CSS). Uplink packets 604 may betransmitted on the SCell in which the preamble was transmitted.

According to an embodiment, initial timing alignment may be achievedthrough a random access procedure. This may involve a UE transmitting arandom access preamble and an eNB responding with an initial TA commandNTA (amount of timing advance) within a random access response window.The start of the random access preamble may be aligned with the start ofa corresponding uplink subframe at the UE assuming NTA=0. The eNB mayestimate the uplink timing from the random access preamble transmittedby the UE. The TA command may be derived by the eNB based on theestimation of the difference between the desired UL timing and theactual UL timing. The UE may determine the initial uplink transmissiontiming relative to the corresponding downlink of the sTAG on which thepreamble is transmitted.

The mapping of a serving cell to a TAG may be configured by a servingeNB with RRC signaling. The mechanism for TAG configuration andreconfiguration may be based on RRC signaling. According to variousaspects of an embodiment, when an eNB performs an SCell additionconfiguration, the related TAG configuration may be configured for theSCell. In an example embodiment, an eNB may modify the TAG configurationof an SCell by removing (releasing) the SCell and adding (configuring) anew SCell (with the same physical cell ID and frequency) with an updatedTAG ID. The new SCell with the updated TAG ID may initially be inactivesubsequent to being assigned the updated TAG ID. The eNB may activatethe updated new SCell and start scheduling packets on the activatedSCell. In an example implementation, it may not be possible to changethe TAG associated with an SCell, but rather, the SCell may need to beremoved and a new SCell may need to be added with another TAG. Forexample, if there is a need to move an SCell from an sTAG to a pTAG, atleast one RRC message, (for example, at least one RRC reconfigurationmessage), may be send to the UE to reconfigure TAG configurations byreleasing the SCell and then configuring the SCell as a part of thepTAG. When an SCell is added/configured without a TAG index, the SCellmay be explicitly assigned to the pTAG. The PCell may not change its TAgroup and may be a member of the pTAG.

The purpose of an RRC connection reconfiguration procedure may be tomodify an RRC connection, (for example, to establish, modify and/orrelease RBs, to perform handover, to setup, modify, and/or releasemeasurements, to add, modify, and/or release SCells). If the receivedRRC Connection Reconfiguration message includes the sCellToReleaseList,the UE may perform an SCell release. If the received RRC ConnectionReconfiguration message includes the sCellToAddModList, the UE mayperform SCell additions or modification.

In LTE Release-10 and Release-11 CA, a PUCCH may only be transmitted onthe PCell (PSCell) to an eNB. In LTE-Release 12 and earlier, a UE maytransmit PUCCH information on one cell (PCell or PSCell) to a given eNB.

As the number of CA capable UEs and also the number of aggregatedcarriers increase, the number of PUCCHs and also the PUCCH payload sizemay increase. Accommodating the PUCCH transmissions on the PCell maylead to a high PUCCH load on the PCell. A PUCCH on an SCell may beintroduced to offload the PUCCH resource from the PCell. More than onePUCCH may be configured for example, a PUCCH on a PCell and anotherPUCCH on an SCell. In the example embodiments, one, two or more cellsmay be configured with PUCCH resources for transmitting CSI/ACK/NACK toa base station. Cells may be grouped into multiple PUCCH groups, and oneor more cell within a group may be configured with a PUCCH. In anexample configuration, one SCell may belong to one PUCCH group. SCellswith a configured PUCCH transmitted to a base station may be called aPUCCH SCell, and a cell group with a common PUCCH resource transmittedto the same base station may be called a PUCCH group.

In an example embodiment, a MAC entity may have a configurable timertimeAlignmentTimer per TAG. The timeAlignmentTimer may be used tocontrol how long the MAC entity considers the Serving Cells belonging tothe associated TAG to be uplink time aligned. The MAC entity may, when aTiming Advance Command MAC control element is received, apply the TimingAdvance Command for the indicated TAG; start or restart thetimeAlignmentTimer associated with the indicated TAG. The MAC entitymay, when a Timing Advance Command is received in a Random AccessResponse message for a serving cell belonging to a TAG and/orif theRandom Access Preamble was not selected by the MAC entity, apply theTiming Advance Command for this TAG and start or restart thetimeAlignmentTimer associated with this TAG. Otherwise, if thetimeAlignmentTimer associated with this TAG is not running, the TimingAdvance Command for this TAG may be applied and the timeAlignmentTimerassociated with this TAG started. When the contention resolution isconsidered not successful, a timeAlignmentTimer associated with this TAGmay be stopped. Otherwise, the MAC entity may ignore the received TimingAdvance Command.

In example embodiments, a timer is running once it is started, until itis stopped or until it expires; otherwise it may not be running. A timercan be started if it is not running or restarted if it is running. Forexample, a timer may be started or restarted from its initial value.

Example embodiments of the disclosure may enable operation ofmulti-carrier communications. Other example embodiments may comprise anon-transitory tangible computer readable media comprising instructionsexecutable by one or more processors to cause operation of multi-carriercommunications. Yet other example embodiments may comprise an article ofmanufacture that comprises a non-transitory tangible computer readablemachine-accessible medium having instructions encoded thereon forenabling programmable hardware to cause a device (e.g. wirelesscommunicator, UE, base station, etc.) to enable operation ofmulti-carrier communications. The device may include processors, memory,interfaces, and/or the like. Other example embodiments may comprisecommunication networks comprising devices such as base stations,wireless devices (or user equipment: UE), servers, switches, antennas,and/or the like.

The amount of data traffic carried over cellular networks is expected toincrease for many years to come. The number of users/devices isincreasing and each user/device accesses an increasing number andvariety of services, e.g. video delivery, large files, images. This mayrequire not only high capacity in the network, but also provisioningvery high data rates to meet customers' expectations on interactivityand responsiveness. More spectrum may therefore needed for cellularoperators to meet the increasing demand. Considering user expectationsof high data rates along with seamless mobility, it may be beneficialthat more spectrum be made available for deploying macro cells as wellas small cells for cellular systems.

Striving to meet the market demands, there has been increasing interestfrom operators in deploying some complementary access utilizingunlicensed spectrum to meet the traffic growth. This is exemplified bythe large number of operator-deployed Wi-Fi networks and the 3GPPstandardization of LTE/WLAN interworking solutions. This interestindicates that unlicensed spectrum, when present, may be an effectivecomplement to licensed spectrum for cellular operators to helpaddressing the traffic explosion in some scenarios, such as hotspotareas. LAA may offer an alternative for operators to make use ofunlicensed spectrum while managing one radio network, thus offering newpossibilities for optimizing the network's efficiency.

In an example embodiment, Listen-before-talk (clear channel assessment)may be implemented for transmission in an LAA cell. In alisten-before-talk (LBT) procedure, equipment may apply a clear channelassessment (CCA) check before using the channel. For example, the CCAmay utilize at least energy detection to determine the presence orabsence of other signals on a channel in order to determine if a channelis occupied or clear, respectively. For example, European and Japaneseregulations mandate the usage of LBT in the unlicensed bands. Apart fromregulatory requirements, carrier sensing via LBT may be one way for fairsharing of the unlicensed spectrum.

In an example embodiment, discontinuous transmission on an unlicensedcarrier with limited maximum transmission duration may be enabled. Someof these functions may be supported by one or more signals to betransmitted from the beginning of a discontinuous LAA downlinktransmission. Channel reservation may be enabled by the transmission ofsignals, by an LAA node, after gaining channel access via a successfulLBT operation, so that other nodes that receive the transmitted signalwith energy above a certain threshold sense the channel to be occupied.Functions that may need to be supported by one or more signals for LAAoperation with discontinuous downlink transmission may include one ormore of the following: detection of the LAA downlink transmission(including cell identification) by UEs, time & frequency synchronizationof UEs, and/or the like.

In an example embodiment, a DL LAA design may employ subframe boundaryalignment according to LTE-A carrier aggregation timing relationshipsacross serving cells aggregated by CA. This may not imply that the eNBtransmissions can start only at the subframe boundary. LAA may supporttransmitting PDSCH when not all OFDM symbols are available fortransmission in a subframe according to LBT. Delivery of necessarycontrol information for the PDSCH may also be supported.

An LBT procedure may be employed for fair and friendly coexistence ofLAA with other operators and technologies operating in an unlicensedspectrum. LBT procedures on a node attempting to transmit on a carrierin an unlicensed spectrum may require the node to perform a clearchannel assessment to determine if the channel is free for use. An LBTprocedure may involve at least energy detection to determine if thechannel is being used. For example, regulatory requirements in someregions, for example, in Europe, may specify an energy detectionthreshold such that if a node receives energy greater than thisthreshold, the node assumes that the channel is not free. While nodesmay follow such regulatory requirements, a node may optionally use alower threshold for energy detection than that specified by regulatoryrequirements. In an example, LAA may employ a mechanism to adaptivelychange the energy detection threshold. For example, LAA may employ amechanism to adaptively lower the energy detection threshold from anupper bound. Adaptation mechanism(s) may not preclude static orsemi-static setting of the threshold. In an example a Category 4 LBTmechanism or other type of LBT mechanisms may be implemented.

Various example LBT mechanisms may be implemented. In an example, forsome signals, in some implementation scenarios, in some situations,and/or in some frequencies, no LBT procedure may performed by thetransmitting entity. In an example, Category 2 (for example, LBT withoutrandom back-off) may be implemented. The duration of time that thechannel is sensed to be idle before the transmitting entity transmitsmay be deterministic. In an example, Category 3 (for example, LBT withrandom back-off with a contention window of fixed size) may beimplemented. The LBT procedure may have the following procedure as oneof its components. The transmitting entity may draw a random number Nwithin a contention window. The size of the contention window may bespecified by the minimum and maximum value of N. The size of thecontention window may be fixed. The random number N may be employed inthe LBT procedure to determine the duration of time that the channel issensed to be idle before the transmitting entity transmits on thechannel. In an example, Category 4 (for example, LBT with randomback-off with a contention window of variable size) may be implemented.The transmitting entity may draw a random number N within a contentionwindow. The size of the contention window may be specified by a minimumand maximum value of N. The transmitting entity may vary the size of thecontention window when drawing the random number N. The random number Nmay be employed in the LBT procedure to determine the duration of timethat the channel is sensed to be idle before the transmitting entitytransmits on the channel.

LAA may employ uplink LBT at the UE. The UL LBT scheme may be differentfrom the DL LBT scheme (for example, by using different LBT mechanismsor parameters), since the LAA UL may be based on scheduled access whichaffects a UE's channel contention opportunities. Other considerationsmotivating a different UL LBT scheme include, but are not limited to,multiplexing of multiple UEs in a single subframe.

In an example, a DL transmission burst may be a continuous transmissionfrom a DL transmitting node with no transmission immediately before orafter from the same node on the same CC. A UL transmission burst from aUE perspective may be a continuous transmission from a UE with notransmission immediately before or after from the same UE on the sameCC. In an example, a UL transmission burst may be defined from a UEperspective. In an example, a UL transmission burst may be defined froman eNB perspective. In an example, in case of an eNB operating DL+UL LAAover the same unlicensed carrier, DL transmission burst(s) and ULtransmission burst(s) on LAA may be scheduled in a TDM manner over thesame unlicensed carrier. For example, an instant in time may be part ofa DL transmission burst or an UL transmission burst.

In an example embodiment, in an unlicensed cell, a downlink burst may bestarted in a subframe. When an eNB accesses the channel, the eNB maytransmit for a duration of one or more subframes. The duration maydepend on a maximum configured burst duration in an eNB, the dataavailable for transmission, and/or eNB scheduling algorithm. FIG. 10shows an example downlink burst in an unlicensed (e.g. licensed assistedaccess) cell. The maximum configured burst duration in the exampleembodiment may be configured in the eNB. An eNB may transmit the maximumconfigured burst duration to a UE employing an RRC configurationmessage.

The wireless device may receive from a base station at least one message(for example, an RRC) comprising configuration parameters of a pluralityof cells. The plurality of cells may comprise at least one license celland at least one unlicensed (for example, an LAA cell). Theconfiguration parameters of a cell may, for example, compriseconfiguration parameters for physical channels, (for example, a ePDCCH,PDSCH, PUSCH, PUCCH and/or the like).

Frame structure type 3 may be applicable to an unlicensed (for example,LAA) secondary cell operation. In an example, frame structure type 3 maybe implemented with normal cyclic prefix only. A radio frame may beT_(f)=307200·T_(s)=10 ms long and may comprise 20 slots of lengthT_(slot)=15360·T_(s)=0.5 ms, numbered from 0 to 19. A subframe may bedefined as two consecutive slots where subframe i comprises of slots 2 iand 2 i+1. In an example, the 10 subframes within a radio frame may beavailable for downlink and/or uplink transmissions. Downlinktransmissions may occupy one or more consecutive subframes, startinganywhere within a subframe and ending with the last subframe eitherfully occupied or following one of the DwPTS durations in a 3GPP Framestructure 2 (TDD frame). When an LAA cell is configured for uplinktransmissions, frame structure 3 may be used for both uplink or downlinktransmission.

An eNB may transmit one or more RRC messages to a wireless device (UE).The one or more RRC messages may comprise configuration parameters of aplurality of cells comprising one or more licensed cells and/or one ormore unlicensed (for example, Licensed Assisted Access-LAA) cells. Theone or more RRC messages may comprise configuration parameters for oneor more unlicensed (for example, LAA) cells. An LAA cell may beconfigured for downlink and/or uplink transmissions.

In an example, the configuration parameters may comprise a firstconfiguration field having a value of N for an LAA cell. The parameter Nmay be RRC configurable. N may be a cell specific or a UE specific RRCparameter. For example, N (for example, 6, 8, 16) may indicate a maximumnumber of HARQ processes that may be configured for UL transmissions. Inan example, one or more RRC messages may comprise configurationparameters of multi-subframe allocation parameters, maximum number ofHARQ processes in the uplink, and/or other parameters associated with anLAA cell.

In an example, a UE may receive a downlink control information (DCI)indicating uplink resources (resource blocks for uplink grant) foruplink transmissions.

In an example embodiment, persistent (also called burst ormulti-subframe) scheduling may be implemented. An eNB may scheduleuplink transmissions by self scheduling and/or cross scheduling. In anexample, an eNB may use UE C-RNTI for transmitting DCIs formulti-subframe grants. A UE may receive a multi-subframe DCI indicatinguplink resources (resource blocks for uplink grant) for more than oneconsecutive uplink subframes (a burst), for example m subframes. In anexample, a UE may transmit m subpackets (transport blocks-TBs), inresponse to the DCI grant. FIG. 11 shows an example multi-subframegrant, LBT process, and multi-subframe transmission.

In an example embodiment, an uplink DCI may comprise one or more fieldsincluding uplink RBs, a power control command, an MCS, the number ofconsecutive subframes (m), and/or other parameters for the uplink grant.

In an example, a multi-subframe DCI may comprise one or more parametersindicating that a DCI grant is a multi-subframe grant. A field in amulti-subframe DCI may indicate the number of scheduled consecutivesubframes (m). For example, a DCI for an uplink grant on an LAA cell maycomprise a 3-bit field. The value indicated by the 3-bit field mayindicate the number of subframes associated with the uplink DCI grant(other examples may comprise, for example, a 1-bit field or a 2-bitfield). For example, a value 000 may indicate a dynamic grant for onesubframe. For example, a field value 011 may indicate a DCI indicatinguplink resources for 4 scheduled subframes (m=field value in binary+1).In an example, RRC configuration parameters may comprise a firstconfiguration field having a value of N for an LAA cell. In an exampleimplementation, the field value may be configured to be less than N. Forexample, N may be configured as 2, and a maximum number of scheduledsubframes in a multi-subframe grant may be 2. In an example, N may beconfigured as 4 and a maximum number of scheduled subframes in amulti-subframe grant may be 4. In an example, N may be a number ofconfigured HARQ processes in an UL. Successive subframes on a carriermay be allocated to a UE when the UE receives a multi-subframe UL DCIgrant from an eNB.

At least one field included in a multi-subframe DCI may determinetransmission parameters and resource blocks used across m consecutivesubframes for transmission of one or more TBs. The DCI may comprise anassignment of a plurality of resource blocks for uplink transmissions.The UE may use the RBs indicated in the DCI across m subframes. The sameresource blocks may be allocated to the UE in m subframes as shown inFIG. 11.

A UE may perform listen before talk (LBT) before transmitting uplinksignals. The UE may perform an LBT procedure indicating that a channelis clear for a starting subframe of the one or more consecutive uplinksubframes. The UE may not perform a transmission at the startingsubframe if the LBT procedure indicates that the channel is not clearfor the starting subframe.

In an example embodiment, a wireless device may receive one or moreradio resource control (RRC) messages comprising configurationparameters for a licensed assisted access (LAA) cell. The one or moreRRC messages may comprise one or more consecutive uplink subframeallocation configuration parameters. In an example, the one or moreconsecutive uplink subframe allocation configuration parameterscomprises a first field, N.

A wireless device may receive a downlink control information (DCI)indicating uplink resources in a number of one or more consecutiveuplink subframes of the LAA cell. The DCI may comprise: the number ofthe one or more consecutive uplink subframes (m); an assignment of aplurality of resource blocks; and a transmit power control command. Thefirst field may indicate an upper limit for the number of the one ormore consecutive uplink subframes.

The wireless device may perform a listen before talk procedureindicating that a channel is clear for a starting subframe of the one ormore consecutive uplink subframes. The wireless device may transmit oneor more transport blocks, via the plurality of resource blocks usedacross the one or more consecutive uplink subframes. At least one fieldincluded in a multi-subframe DCI may determine transmission parametersand resource blocks used across m consecutive subframes for transmissionof one or more TBs. The DCI may comprise an assignment of a plurality ofresource blocks for uplink transmissions. The UE may use the RBsindicated in the DCI across m subframes. The same resource blocks may beallocated to the UE in m subframes.

A DCI indicating a multi-subframe grant (MSFG) may be supported incarrier aggregation, for example, for an unlicensed cell (e.g. an LAAcell). Design of a multi-subframe grant (MSFG) may take into account thedesign of existing DCIs used for single subframe grants. For example,current LTE-A DCI Format 0 and 4 may be used for uplink grants with andwithout special multiplexing. DCI Format 0 and 4 may be updated tosupport MSFGs with or without special multiplexing.

A MSFG may allow a UE to transmit on multiple consecutive uplinksubframes based on some common set of transmission parameters. Some oftransmission parameters, like MCS level, power control command, and/orresource assignments (e.g. RBs) may be common across scheduledsubframes. Some parameters, like HARQ process ID, RV and/or NDI may besubframe specific. The DCI indicating a MSFG may comprise one or moreparameters indicating the number of consecutive subframes allowed fortransmission according to the grant. In an example, the parameters whichmay be configured by DCI may include the number of consecutive subframes(m) associated with the MSFG. A MSFG may provide resource allocation forsubframes starting from subframe n and ending at subframe n+m−1.

When a UE receives a multi-subframe grant (MSFG) for UL transmissions ofm consecutive subframes on an LAA carrier, the UE may perform LBT beforetransmission on the scheduled subframes. A successful LBT may befollowed by a reservation signal if transmission of the reservationsignals is allowed and/or needed. The UE's LBT may or may not succeedbefore start of a first allowed transmission symbol of subframe n. In anexample, if UE's LBT is successful before a first allowed transmissionsymbol of subframe n, the UE may transmit data according tomulti-subframe DCI. The UE may transmit data (TBs) when LBT issuccessful.

The DCI indicating a MSFG may include parameters for UEs behavior due toLBT. A multi-subframe DCI may include possible LBT time interval(s)and/or at least one LBT configuration parameter. The DCI may indicateone or more configuration parameters for LBT process beforetransmissions corresponding to a MSFG.

In an example, one or more DCI may indicate configuration fortransmission of reservation signals, format of reservation signals,allowed starting symbol, and/or LBT intervals/symbols associated with aMSFG. For example, the DCI may indicate a PUSCH starting position in asubframe. LBT procedure may be performed before the PUSCH startingposition. One or more DCI may comprise configuration parametersindicating reservation signals and/or partial subframe configuration. Inan example embodiment, transmission of reservation signals and/orpartial subframe for a multi-subframe grant may not be supported.

In an example, a UE may perform LBT (e.g. in a symbol) before subframe nstarts. In an example, a UE may perform LBT in a first symbol ofsubframe n. A UE may be configured to perform LBT in one or more allowedsymbols of a subframe, or within a configured period/interval in asubframe. The multi-subframe grant DCI may include possible LBT timeinterval(s) and/or at least one LBT configuration parameter. Forexample, DCI may indicate that PUSCH starts in symbol 0 and a LBTprocedure is performed before PUSCH starts (e.g. last symbol of aprevious subframe). For example, DCI may indicate that PUSCH starts insymbol 1 and an LBT procedure is performed before PUSCH starts (e.g. insymbol 0).

In an example, one or more LBT configuration parameters may be indicatedin an RRC message. In an example, one or more RRC message configuring anLAA cell may comprise at least one field indicating an LBT interval.

An eNB may transmit to a UE one or more RRC messages comprisingconfiguration parameters of a plurality of cells. The plurality of cellsmay comprise one or more licensed cell and one or more unlicensed (e.g.LAA) cells. The eNB may transmit one or more DCIs for one or morelicensed cells and one or more DCIs for unlicensed (e.g. LAA) cells toschedule downlink and/or uplink TB transmissions on licensed/LAA cells.

A UE may receive at least one downlink control information (DCI) from aneNB indicating uplink resources in m subframes of a licensed assistedaccess (LAA) cell. In an example embodiment, an MSFG DCI may includeinformation about RV, NDI and HARQ process ID of a subframe of thegrant. For example, when a grant is for m subframes, the grant mayinclude at least m set of RVs and NDIs for HARQ processes associatedwith m subframes in the grant. In an example, subframe specificparameters may comprise one or more of the following for each subframeof a MSFG burst: M bits for RV, example 2 bits for 4 redundancyversions; and/or 1 bit for NDI.

In an example, common parameters may include: TPC for PUSCH, Cyclicshift for DM RS, resource block assignment, MCS and/or spatialmultiplexing parameters (if any, for example included in DCI format 4),LBT related parameters applied to the uplink burst, and/or Otherparameters, e.g. one or more multi-subframe configuration parameters.The MSFG DCI may comprise an RB assignment field, an MCS field, an TPCfield, an LBT field applicable to all the subframes associated with aMSFG. These parameters may be the same for different subframes of a MSFGburst. Resource block assignment, MCS and/or spatial multiplexingparameters may change from one MSFG burst to another MSFG burst.

Uplink grant DCI scheduling a PUSCH for an LAA cell may be a signaled asone of a single-subframe or multi-subframe grant. An eNB may transmit asingle-subframe or multi-subframe UL grant on (e)PDCCH, e.g. using DCIformat 0A/4A/0B/4B, instructing a UE to transmit one or two transportblocks across N consecutive subframes (N>=1, e.g. N=1, 2, 3, or 4) of aPUSCH. An eNB may transmit to a UE an UL grant for subframe (SF) n, r(e.g. r=4, 5, or 6, etc) subframes in advance of a scheduled subframe.

For LAA uplink, DCI 0B and DCI 4B may schedule PUSCH transmission inmaximum N_sf subframes, where N_sf is configurable by (UE-specific) RRCsignaling. When an eNB configures one or more parameters via RRCsignaling or when one or more parameters is RRC configured, it impliesthat an eNB transmits one or more RRC messages comprising configurationparameters of one or more cells. The configuration parameters mayindicate that the one or more parameters are configured in the UE. Forexample, an eNB may transmit an RRC message (UE-specific) comprisingconfiguration parameters of one or more LAA cells. The RRC message maycomprise a parameter indicating N_sf, one or more LBT parameters, and/oruplink/downlink channel parameters.

DCI 0B may indicate PUSCH multi-subframe scheduling (e.g. with TM1) foran LAA SCell. DCI 4B may indicate PUSCH multi-subframe scheduling (e.g.with TM2) for an LAA SCell. N_sf parameter value range may be N_min toN_max. For example, value of N_min: 2, Value of N_max is 4.

In an example, RRC signaling may enable or disable DCI 0B and/or DCI 4B.DCI format 0B/4B may comprise number of scheduled subframes fieldindicating a number of scheduled subframes. DCI format 0B/4B maycomprise a HARQ process number field indicating HARQ process IDs for thescheduled subframes by indicating a HARQ process ID for the firstscheduled subframe. HARQ p_ids for other subframes may be derived by agiven rule. For example, the HARQ p_ids for other subframes may beconsecutive with the indicated HARQ process IDs, modulo max number ofHARQ processes. DCI format 0B/4B may indicate RVs for the scheduledsubframes by indicating an RV value (e.g. 1-bit or 2-bit RV value) perscheduled subframe (regardless of the number of scheduled transportblocks). For example, DCI format 0B/4B may indicate RV of 0 or 2 for ascheduled subframe.

In an example, a UE may be configured to detect multiple uplink grantswhich may be chosen without restriction from DCI 0A/4A/0B/4B. In anexample, maximum number of uplink grants to be transmitted for a singleUE in a subframe is 4. DCI 0A may indicate PUSCH single-subframescheduling with TM1 for LAA SCell. DCI 4A may indicate PUSCHsingle-subframe scheduling with TM2 for LAA SCell. A single UL grantscheduling multiple subframes may schedule consecutive subframes forPUSCH transmission. A timing offset is counted from subframe N+4+k, andk is signaled with (for example, 3 bits, [0 . . . 7] SFs). An eNB mayimplement 2-step scheduling.

Transmission by UEs in the UL of an LAA cell may be subject to somemaximum channel occupancy time (MCOT). Maximum channel occupancy mayconsider downlink transmissions by an eNB and subsequent UEtransmissions in the uplink, for example if UE transmits uplink within ashort period (e.g. 16 micro-second) of downlink transmission.

In an example embodiment, an uplink grant DCI (e.g. DCI format 0A, 4A,0B, 4B) may further comprise a resource block assignment fieldindicating the resource allocation in UL subframe(s), a PUSCH startingposition field indicating a PUSCH starting position, a PUSCH endingsymbol field indicating whether PUSCH transmission include the lastsymbol of an uplink subframe, channel access type field indicating achannel access (LBT) type, and/or a channel access (LBT) priority classfield indicating a channel access priority.

Uplink grant DCI 0B and 4B may further comprise a number of scheduledsubframes field indicating the number of scheduled uplink subframes.

In an example, a two-bit PUSCH starting position field may indicate oneof the four PUSCH starting positions: symbol 0 (value 00), 25 μs insymbol 0 (value 01), (25+TA)μs in symbol 0 (value 10), and symbol 1(value 11). For example, PUSCH ending symbol field may be one bit,wherein value 0 indicates that PUSCH ending symbol is the last symbol ofthe subframe and value 1 indicates that PUSCH ending symbol is thesecond to last symbol of the subframe. In an example, a one-bit channelaccess type field may indicate one of the Type 1 or Type 2 channelaccess procedures. In an example, a two-bit channel access priorityclass field may indicate a channel access priority of zero, one, two, orthree.

A UE may perform a listen before talk (LBT) procedure before uplinktransmission. There are multiple channel access (LBT) procedures, whichUE may perform if needed prior to UE transmission in the uplink. A UEmay select an LBT procedure before transmission of uplink signals (e.g.a TB, SRS, etc) based on type or priority of the uplink signals, and/orLBT type field and/or LBT priority field in the DCI. An eNB may transmitUE specific DCIs to a UE. The eNB may transmit to the UE an uplink grantDCI scheduling a PUSCH. The uplink grant DCI may comprise a parameterindicating an LBT (a channel access) type. For example, the channelaccess type (e.g. at least for PUSCH) may be one of 25/16 us LBT (LBTType 2) or category 4 LBT (LBT Type 1).

The control information may comprise one or more information elementsindicating LBT type and/or LBT parameters. In an example, a UE mayperform a short one shot LBT, e.g., LBT category 2 (LBT Type 2), or LBTover a contention window, e.g. LBT category 4 (LBT Type 1). The eNB maytransmit control information (e.g. uplink grant DCI) to a UE comprisingLBT parameters including the type, timing, and/or contention windowsize. In an example scenario, a UE may transmit uplink signals withoutperforming LBT procedure. For example, in a multi-subframe transmission,a UE may perform LBT for the first subframe and then if LBT for thefirst subframe is successful (indicates a clear channel) the UE maytransmit subsequent subframes without performing LBT for the subsequentsubframes.

In an example, an eNB may transmit to a UE a uplink DCI comprising oneor more LBT information fields in a predefined format. For example, thepredefined format may be a one-bit field indicating an LBT (channelaccess) type. For example, a two-bit field may indicate LBT type andparameters, e.g. a 2 bit LBT type field indicating No-LBT, LBT type 1and/or LBT type 2 for 00, 01 and 10 states, respectively.

An eNB may designate some time intervals, e.g. one or more symbols atthe beginning and/or end of one or more subframes, during which ULtransmissions may be punctured. This may allow multiple users to bescheduled on a subframe without their LBTs blocking each other.

A later start time may create opportunities for other nodes/UEs to runLBT and transmit on the same subframe if UE LBT test is successful. AneNB may transmit to a UE an UL grant DCI comprising a PUSCH startingposition field indicating a starting uplink transmission time. When astarting symbol is included in a multi-subframe grant, the starting timemay be applicable to first subframe of a multi-subframe transmission,e.g. first subframe may start from symbol 1 while others start fromsymbol 0. In an example, transmission on UL may start at the followingtimes in an UL subframe: start of DFTS-OFDM symbol 0, start of DFTS-OFDMsymbol 1, 25 us+TA value after start of DFTS-OFDM symbol 0, and 25 usafter start of DFTS-OFDM symbol 0. Other starting times may be defined.In an example, gaps may be created by a UE subframe timing adjustmentinstead of using a partial OFDM symbol if a TA offset is dynamicallysignaled.

In an example, an eNB may transmit to a UE an uplink grant DCIscheduling PUSCH indicating an ending symbol of PUSCH transmission. Thecontrol information may indicate that PUSCH ends at end of a subframe orend 1 or few symbols earlier than the end of a subframe, e.g. on symbol12 of a 13-symbol subframe. An early termination of transmission maycreate opportunities for other nodes (e.g. UEs, and/or eNBs) to performLBT and transmit on the following subframe if the LBT procedureindicates a clear channel. The blanked symbols may also be used forother UEs SRS or other UL transmission if configured and directed by theeNB. An eNB may transmit to a UE an UL grant DCI comprising a PUSCHending symbol field. When a PUSCH ending symbol field is included in amulti-subframe grant (e.g. DCI 0B/4B), the ending symbol may beapplicable to the last subframe of the multi-subframe transmission, e.g.PUSCH transmission in the last subframe of a multi-subframe transmissionmay not comprise the last symbol and earlier subframes may comprise thelast symbol.

In an example embodiment, for a transmission burst with PDSCH(s) and/orPUSCH(s) scheduled by the eNB for which channel access has been obtainedusing Channel Access Priority Class P (1 . . . 4), E-UTRAN/UE may enablethe following. Transmission burst may refer to DL transmissions from theeNB and scheduled UL transmissions from the UEs starting after asuccessful LBT. For example, the transmission duration of thetransmission burst may not exceed the minimum duration needed totransmit available buffered traffic corresponding to Channel AccessPriority Class(es)≤P. The buffered traffic includes available traffic inDL at the eNB and traffic available for transmission at scheduled UEs asper the latest buffer status information from each UE. The transmissionduration of the transmission burst may not exceed the Maximum ChannelOccupancy Time (MCOT) for Channel Access Priority Class P. In anexample, additional traffic corresponding to Channel Access PriorityClass(es)>P may be included in the transmission burst once no morebuffered traffic corresponding to Channel Access Priority Class(es)≤P isavailable for transmission and the transmission duration of thetransmission burst as defined above has not yet expired. In such cases,E-UTRAN/UE may increase occupancy of the remaining transmissionresources in the transmission burst with this additional traffic.

When an eNB transmits an uplink grant DCI for PUSCH transmission onsubframe n+1 and uplink signals are scheduled by the eNB fortransmission in subframe n, the eNB may or may not know if the UE hasmanaged to transmit in subframe n. In an example scenario, an eNB maytransmit an UL grant for subframe n as a single-subframe grant in SFn−4, followed by a single (or multi) subframe grant sent on subframe n−3for UL transmission on or starting on subframe n+1. In such case the eNBmay not know at the time of grant for SF n+1, e.g. during SF n−3, if theUE has successfully passed LBT process for subframe n. The UL grant forsubframe n+1 may provide UE with LBT parameters. In an example scenario,uplink transmissions may be inefficient if the UE performs LBT based onLBT instructions transmitted by the eNB. In an example scenario, when ULtransmission on subframe n is scheduled as part of multi-subframe grant,the eNB may know if UE is transmitting on subframe n, when it schedulestransmission on subframe n+1. In such case and if MCOT for UE has notexpired, the eNB may not need to provide any LBT information or mayallow the UE to transmit data without LBT. There is a need to defineenhanced processes for a UE to determine whether to perform or not toperform LBT based on the information received from an eNB and uplinktransmissions in a prior subframe.

A UE may determine to perform an LBT procedure for subframe n+1, atleast based on: LBT instructions received from the eNB for subframe n+1(e.g. LBT parameters, starting time, etc), expiry of MCOT duration forUE's ongoing burst in subframe n+1, UE uplink transmission in subframen, and/or ending symbols of subframe n.

In an example scenario, a UE may transmit uplink signals in subframe n.The eNB may transmit to the UE an uplink grant DCI scheduling PUSCH forsubframe n+1. The uplink grant DCI may include transmission fieldsand/or LBT instructions/fields. The UE may or may not perform an LBTprocedure before transmitting on subframe n+1. In an example, the eNBmay transmit a DCI comprising a PUSCH ending symbol field indicatingthat the UE ends PUSCH at the second to last symbol of subframe n, orthe eNB may transmit a DCI (for subframe n+1) comprising PUSCH startingposition field indicating that PUSCH starting position is not thebeginning of symbol 0 of subframe n+1. Other users may perform LBT inthe blanked interval (no UE uplink transmission) and may transmit dataafter a successful LBT procedure (LBT procedure indicating a clearchannel). Such mechanism may enable multi-user scheduling.

In an example, a UE may receive from the eNB an uplink grant DCI tostart transmitting on subframe n+1 and uplink transmissions by the UEends on subframe n. The UE may perform an LBT procedure for transmissionin subframe n+1.

In an example, if an UL grant (scheduling a PUSCH transmission forsubframe n+1) comprises an LBT type field indicating a Type 1 channelaccess (LBT) procedure, the UE may use Type 1 channel access procedurefor transmitting transmissions including the PUSCH transmissiondepending on example criteria described in this specification. In anexample, if an UL grant (scheduling a PUSCH transmission for subframen+1) comprises an LBT type field indicating a Type 2 channel access(LBT) procedure, the UE may use Type 2 channel access procedure fortransmitting transmissions including the PUSCH transmission depending onexample criteria described in this specification. Based on examplecriteria, the UE may not consider LBT type instructed by the eNB and maycontinue uplink transmission in a subframe n+1 without performing LBTfor transmission in subframe n+1.

In an example, a PUSCH starting time of 0 implies that PUSCH may startfrom the beginning of symbol 0. A PUSCH starting time of 1 or delayedimplies that PUSCH may start from beginning of symbol 1 or after aninterval (delay) from the beginning of symbol 0 (e.g. 25 usec, TA+25usec).

In an example, when a UE receives from an eNB an uplink grant DCI forSubframe n+1 while the UE has not transmitted in subframe n, the UE mayapply LBT prior to transmission on subframe n+1. In an exampleembodiment, if the DCI indicates that the starting time of subframe n+1is 1 or delayed, the UE may perform LBT on symbol 0. If the DCIindicates that the starting time of subframe n+1 is 0, the UE mayperform LBT on symbol 13 of subframe n (if LBT in symbol 13 is allowed).In an example, if the DCI indicates that the starting time of subframen+1 is 0 and LBT in symbol 13 is not allowed, the UE may consider thisas an error case and ignore the grant. In an example, such indication of0 starting by the eNB may imply that UE may transmit subframe n withoutLBT. This may be the case when SF n+1 starts shortly, e.g. within 16 us,following eNB's DL burst and ends before eNB's MCOT expires.

In an example, when a UE receives from the eNB an uplink grant DCI forsubframe n+1 while it has transmitted on subframe n, the UE may continuetransmitting on subframe n+1 based on the uplink grant withoutperforming additional LBT if the UE uplink transmission is still withinits MCOT. In an example, the eNB may instruct a UE to pause itstransmission, even within UE's MCOT, to allow other UEs with pending ULgrants perform LBT and transmit on subframe n+1 if their LBT issuccessful. The eNB may use LBT parameters in the UL grant to controlsuch UEs behavior.

In an example embodiment, if an eNB sets one or more blank symbols usingan uplink grant for subframe n and an uplink grant for subframe n+1,e.g. leaving symbol 13 of SF n and/or symbol 0 (or part of symbol 0) ofSF n+1 as blank, it implies that the UE may pause and apply LBT beforetransmitting in subframe n+1. In an example, if an eNB sets the lastsymbol of subframe n as symbol 12, e.g. leaving symbol 13 a blanksymbol, and sets starting symbol of SF n+1 as 0, then the UE may performan LBT procedure during symbol 13 of subframe n before transmitting onsymbol 0 or subframe n.

In an example, if UE's MCOT expires before the end of subframe n+1, thenthe UE may not transmit on subframe n+1 without an LBT procedure. Inthis case, if the eNB's grants for subframes n and n+1 provision forblank time interval for LBT, the UE may perform LBT on those symbols. Inan example if the eNB has not provisioned for a blank LBT time intervalwhile MCOT expires before end of subframe n+1, the UE may wait for a newgrant or perform LBT on a default symbol, e.g. symbol 0 of SF n+1.

In an example, the eNB may indicate the LBT interval as timing gap to becalculated by UEs based on their Timing Advanced in Uplink, e.g. TA+25micro-seconds. The eNB transmits UL grants at least r, e.g. r=4,subframe ahead of scheduled subframe to allow UEs to process the TB andprepare their transmission according grant parameters. In an example,where the eNB sends LBT parameters on an UL grant such parameters needto be determined r subframes before start of UE's transmission.

In an example embodiment, the eNB may transmit to the UE an uplink grantDCI for transmission in subframe n+1. The uplink grant DCI for subframen+1 may comprise an LBT type field indicating an LBT type. The uplinkgrant DCI for subframe n+1 may comprise a PUSCH starting position fieldindicating that PUSCH transmission starts from beginning of symbol 0.

In an example, if a UL grant (scheduling a PUSCH transmission forsubframe n+1) comprises an LBT type field indicating a Type 1 channelaccess (LBT) procedure, the UE may conditionally use the Type 1 channelaccess procedure for transmitting transmissions including the PUSCHtransmission depending on example criteria described in thisspecification. In an example, if a UL grant (scheduling a PUSCHtransmission for subframe n+1) comprises an LBT type field indicating aType 2 channel access (LBT) procedure, the UE may conditionally use theType 2 channel access procedure for transmitting transmissions includingthe PUSCH transmission depending on example criteria described in thisspecification. Based on example criteria, the UE may not consider theLBT type instructed by the eNB and may continue uplink transmission in asubframe n+1 without performing LBT for transmission in subframe n+1.There is a need to define enhanced processes for a UE to determinewhether to perform or not to perform LBT based on the informationreceived from an eNB and uplink transmissions in a prior subframe.

The eNB may not be aware of the connection state of the wireless deviceand wireless device uplink transmissions in a prior subframe at the timean uplink grant is transmitted by the eNB. In an example embodiment, thewireless device may determine whether the wireless device shouldconsider or should not consider the LBT type provided by the eNB in theuplink grant DCI. Example embodiments enable the eNB to provide LBTinstructions in an uplink grant for transmission in a subframe. Inaddition, example embodiments enable the UE to determine whether the UEshould perform or not perform an LBT procedure based on the eNBinstructions. Example embodiments enable both the eNB and the UE toprovide input on an LBT procedure for transmission in a subframe. Insome scenarios, the UE may ignore the LBT instructions by the eNB andtransmit uplink signals without performing an LBT procedure. Exampleembodiments enhance uplink transmission efficiency by a wireless deviceand reduces UE power consumption and processing requirements.

In an example embodiment, the uplink grant DCI may comprise an LBT typefield indicating that a UE may perform LBT for subframe n+1. In anexample, the uplink grant DCI may further comprise a PUSCH startingposition indicating that PUSCH in subframe n+1 starts at the beginningof symbol 0 of subframe n+1. The uplink grant DCI may include at leastone LBT parameter for uplink transmissions by the UE in subframe n+1.This indicates that the UE may conditionally perform an LBT procedurefor subframe n+1 depending at least on transmissions in subframe n. Ifthe UE successfully transmits (e.g. due to a successful LBT) uplinksignals in subframe n including the last symbol, then UE may not performLBT for subframe n+1. An example is shown in FIG. 12, Example A. In thiscase, the UE is scheduled to transmit transmissions (e.g. includingPUSCH) without gaps between subframes n and n+1, and the UE performs atransmission in subframe n (including the last symbol of subframe n),and the UE may continue transmission in subframes n+1 without performingan LBT procedure for subframe n+1. This is irrespective of uplink grantDCI for subframe n+1 indicating an LBT procedure Type 1 or an LBTprocedure Type 2 for subframe n+1. The UE may not perform an LBTprocedure according to LBT type field in the uplink grant DCI field forsubframe n+1. The UE may ignore the LBT type field in the uplink grantDCI for subframe n+1. In an example, the UE may transmit in subframe nafter accessing the carrier, e.g., according to one of Type 1 or Type 2UL channel access (LBT) procedures.

If the UE does not transmit signals in subframe n (e.g. due to LBTindicating busy channel) or if the UE does not transmit uplink signalsin the last symbol of subframe n, then the UE may perform an LBTprocedure for subframe n+1. As described above, interpretation of an LBTfield in the uplink grant DCI field for subframe n+1 may depend onwhether signals are transmitted in subframe n (including the lastsymbol) or not. If no uplink transmission is scheduled for subframe n,or if uplink transmissions in subframe n ends in the symbol before thelast symbol of subframe n (e.g. transmission ends at symbol 12 and doesnot comprise the last symbol), then the UE may perform an LBT procedurefor transmissions in subframe n+1. An example is shown in FIG. 12,Example B. If the transmission in subframe n+1 starts later than thebeginning of symbol 0 of subframe n+1 (e.g. starting from the 2nd symbolor after the beginning of symbol 0), then the UE may perform LBT fortransmission in subframe n+1. An example is shown in FIG. 13. When thereis a transmission gap between subframes n and n+1, then the UE mayperform LBT for transmission in subframe n+1. When the UE is scheduledto transmit transmissions (e.g. including PUSCH) without gaps betweensubframes n and n+1, and the UE performs a transmission in subframe n(including the last symbol of subframe n), the UE may continuetransmission in subframes n+1 without performing an LBT procedure,irrespective of an LBT parameter in the uplink grant DCI for subframen+1.

In an example embodiment, common DCI may comprise subframe specific LBTinformation. Such common DCI may or may not be supported or transmittedby eNB depending on eNB/UE implementation. LBT parameters may beincluded in an UL grant and/or may be included in a common DCI e.g. aDCI transmitted on (e)PDCCH masked with CC-RNTI.

In an example, when a UE receives a grant for SF n+1 while it hastransmitted on subframe n, the UE may continue transmitting on subframen+1 based on a new grant without performing additional LBT if the UEuplink transmission is within its MCOT. In an example, the eNB mayinstruct a UE to pause its transmission, even within UE's MCOT, to allowother UEs with pending UL grants perform LBT and transmit on subframen+1 if their LBT is successful. The eNB may use LBT parameters in the ULgrant or common DCI (if supported) to control such a UE behavior.

In an example embodiment, in addition or instead of sending LBTparameters in an UL grant, the eNB may transmit subframe specific LBTcontrol information in a common DCI. Such information may include LBTtype and parameters to be used and/or timing of LBT intervals, e.g.across multiple subframes. Common signaling of LBT designated timeintervals enables concurrent multi-user LBT and scheduling. In anexample, the common DCI may include a bitmap of length N which indicatesover which of the following N subframes the first symbol should beblanked. In an example, a bitmap of length M may be used to show overwhich of the following M subframes the last symbol of subframe may bekept blanked (punctured).

In an example, an eNB may send LBT parameters on a common DCI, the UEmay apply the LBT parameters as early as the following subframe. Forexample, common DCI in subframe n may be applied to subframe n+p,wherein e.g. p=1, 2.

In an example embodiment, the eNB may transmit common DCI to convey LBTparameters and symbols/timings. UEs monitoring DL for this common DCImay perform LBT on a subframe n+1 based on relevant LBT parametersincluded in the latest received common DCI for this subframe. Forexample, when common DCI including LBT parameters is received insubframe n-k, and n, the UE may apply the common DCI in subframe n fortransmission in subframe n+1.

In an example embodiment, the eNB may include LBT parameters andsymbols/timings in both UL grant and in common DCI. In this case, the UEmay perform LBT based on one or combination of information received fromeNB. In an example, when common DCI and uplink grant LBT parameters arereceived in the subframe, a UE may consider LBT parameters in the uplinkgrant. In an example, the UE follows the LBT information in an UL grantfor a given subframe n+1, if available, regardless of any information inthe common DCI. In an example the UE may apply a most recent LBTinformation about subframe n+1 as received from the eNB on acorresponding UL grant or from a common DCI. For example, if an UL grantfor subframe n+1 that include LBT directions is received in subframe n−3while common DCI with other LBT parameters for the subframe n+1 isreceived on subframe n then UE may follow the LBT parameters in commonDCI.

According to various embodiments, a device such as, for example, awireless device, a base station and/or the like, may comprise one ormore processors and memory. The memory may store instructions that, whenexecuted by the one or more processors, cause the device to perform aseries of actions. Embodiments of example actions are illustrated in theaccompanying figures and specification.

FIG. 14 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1410, a wireless device may receive an uplinkgrant for a licensed assisted access (LAA) cell. The uplink grant maycomprise a physical uplink shared channel (PUSCH) starting positionfield and a listen-before-talk (LBT) type field. The PUSCH startingposition field may indicate a PUSCH starting position in a subframe ofthe LAA cell. The LBT type field may indicate at least one of a firstLBT type or a second LBT type for the subframe. According to anembodiment, the first LBT type may be a Category 4 LBT. According to anembodiment, the second LBT type is a Category 2 LBT. According to anembodiment, the PUSCH starting position field may indicate that thePUSCH transmissions in the subframe starts from a beginning of symbolzero. According to an embodiment, the PUSCH starting position field mayindicate one of the following PUSCH starting positions: symbol 0, 25 μsin symbol 0, (25+TA)μs in symbol 0, or symbol 1. According to anembodiment, the uplink grant may be one of: a single-subframe uplinkgrant; or multi-subframe uplink grant. According to an embodiment, theuplink grant may further comprise a PUSCH ending symbol field indicatingwhether the PUSCH is transmitted in a last symbol of the subframe.According to an embodiment, the wireless device may further receive asecond uplink grant for the preceding adjacent subframe.

At 1420, a determination may be made, at least based on, uplinktransmissions by the wireless device in a preceding adjacent subframe ofthe LAA cell: to perform an LBT procedure for transmission of uplinksignals in the subframe, or to transmit the uplink signals withoutperforming the LBT procedure for the subframe, regardless of the LBTtype field indicating the first LBT type or the second LBT type.According to an embodiment, the determination by the wireless device maybe further based, at least, on expiry of a maximum channel occupancytime (MCOT).

According to an embodiment, a determination may be made to perform theLBT procedure for transmission of the uplink signals in the subframe inresponse to the wireless device having a transmission gap between thepreceding adjacent subframe and the subframe. According to anembodiment, a determination may be made to transmit the uplink signalsin the subframe without performing the LBT procedure in response to thewireless device transmitting without a transmission gap between thepreceding adjacent subframe and the subframe. According to anembodiment, a determination may be made to perform the LBT procedure fortransmission of the uplink signals in the subframe in response to thePUSCH starting position field indicating that the PUSCH transmissions inthe subframe starts later than a beginning of symbol zero. According toan embodiment, a determination may be made to perform the LBT procedurefor transmission of the uplink signals in the subframe in response tothe wireless device not transmitting first uplink signals in at least alast symbol of the preceding adjacent subframe. According to anembodiment, a determination may be made to transmit the uplink signalswithout performing the LBT procedure for the subframe in response to thewireless device transmitting in a last symbol of the preceding adjacentsubframe.

According to an embodiment, the wireless device may further receive atleast one message comprising configuration parameters of the LAA cell.At 1430, the uplink signals in the subframe may be transmitted via theLAA cell.

A wireless device may receive an uplink grant for transmission insubframe n+1 of a licensed assisted access (LAA) cell (e.g. at 1410).The uplink grant may comprise a physical uplink shared channel (PUSCH)starting position field, and a listen-before-talk (LBT) type field. ThePUSCH starting position field may indicate that PUSCH transmissions inthe subframe n+1 starts from a beginning of symbol zero. The LBT typefield may indicate one of a first LBT type or a second LBT type for thesubframe n+1. According to an embodiment, the first LBT type may be aCategory 4 LBT. According to an embodiment, the second LBT type may be aCategory 2 LBT. According to an embodiment, the PUSCH starting positionfield indicate one of the following PUSCH starting positions: symbol 0,25 μs in symbol 0, (25+TA)μs in symbol 0, or symbol 1.

According to an embodiment, the uplink grant may be one of: asingle-subframe uplink grant; or multi-subframe uplink grant. Accordingto an embodiment, the uplink grant may further comprise a PUSCH endingsymbol field indicating whether the PUSCH is transmitted in a lastsymbol of the subframe n+1. According to an embodiment, the wirelessdevice may further receive a second uplink grant for subframe n.

The wireless device may determine (e.g. at 1420), at least based onuplink transmissions by the wireless device in subframe n, whether to:perform an LBT procedure for transmission of uplink signals in thesubframe n+1, or transmit the uplink signals in the subframe n+1 withoutperforming an LBT procedure, regardless of whether the LBT type fieldindicates the first LBT type or the second LBT type. According to anembodiment, the wireless device may determine to perform the LBTprocedure for transmission of the uplink signals in subframe n+1 inresponse to the wireless device not transmitting uplink signals in atleast a last symbol of the subframe n of the LAA cell. According to anembodiment, the wireless device may transmit the uplink signals in thesubframe n+1 without performing the LBT procedure in response to thewireless device transmitting in a last symbol of subframe n. Accordingto an embodiment, the wireless device may perform the LBT procedure fortransmission of uplink signals in the subframe n+1 in response to thewireless device having a transmission gap between the subframe n and thesubframe n+1. According to an embodiment, the wireless device maytransmit the uplink signals in the subframe n+1 without performing theLBT procedure in response to the wireless device transmitting without atransmission gap between the subframe n and the subframe n+1. Accordingto an embodiment, the determining by the wireless device, may be furtherbased, at least, on expiry of a maximum channel occupancy time (MCOT)duration.

According to an embodiment, the wireless device may further receive atleast one message comprising configuration parameters of the LAA cell.The uplink signals may be transmitted in the subframe n+1 (e.g. at1430).

In this specification, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” In this specification,the term “may” is to be interpreted as “may, for example.” In otherwords, the term “may” is indicative that the phrase following the term“may” is an example of one of a multitude of suitable possibilities thatmay, or may not, be employed to one or more of the various embodiments.If A and B are sets and every element of A is also an element of B, A iscalled a subset of B. In this specification, only non-empty sets andsubsets are considered. For example, possible subsets of B={cell1,cell2} are: {cell1}, {cell2}, and {cell1, cell2}.

In this specification, parameters (Information elements: IEs) maycomprise one or more objects, and each of those objects may comprise oneor more other objects. For example, if parameter (IE) N comprisesparameter (IE) M, and parameter (IE) M comprises parameter (IE) K, andparameter (IE) K comprises parameter (information element) J, then, forexample, N comprises K, and N comprises J. In an example embodiment,when one or more messages comprise a plurality of parameters, it impliesthat a parameter in the plurality of parameters is in at least one ofthe one or more messages, but does not have to be in each of the one ormore messages.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an isolatableelement that performs a defined function and has a defined interface toother elements. The modules described in this disclosure may beimplemented in hardware, software in combination with hardware,firmware, wetware (i.e hardware with a biological element) or acombination thereof, all of which are behaviorally equivalent. Forexample, modules may be implemented as a software routine written in acomputer language configured to be executed by a hardware machine (suchas C, C++, Fortran, Java, Basic, Matlab or the like) or amodeling/simulation program such as Simulink, Stateflow, GNU Octave, orLabVIEWMathScript. Additionally, it may be possible to implement modulesusing physical hardware that incorporates discrete or programmableanalog, digital and/or quantum hardware. Examples of programmablehardware comprise: computers, microcontrollers, microprocessors,application-specific integrated circuits (ASICs); field programmablegate arrays (FPGAs); and complex programmable logic devices (CPLDs).Computers, microcontrollers and microprocessors are programmed usinglanguages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDsare often programmed using hardware description languages (HDL) such asVHSIC hardware description language (VHDL) or Verilog that configureconnections between internal hardware modules with lesser functionalityon a programmable device. Finally, it needs to be emphasized that theabove mentioned technologies are often used in combination to achievethe result of a functional module.

The disclosure of this patent document incorporates material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, for the limited purposes required by law, butotherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the spirit and scope. In fact, after reading theabove description, it will be apparent to one skilled in the relevantart(s) how to implement alternative embodiments. Thus, the presentembodiments should not be limited by any of the above describedexemplary embodiments. In particular, it should be noted that, forexample purposes, the above explanation has focused on the example(s)using a licensed assisted access cell in communication systems. However,one skilled in the art will recognize that embodiments of the disclosuremay also be implemented in a system comprising one or more stand-aloneunlicensed cells. The disclosed methods and systems may be implementedin wireless or wireline systems. The features of various embodimentspresented in this disclosure may be combined. One or many features(method or system) of one embodiment may be implemented in otherembodiments. Only a limited number of example combinations are shown toindicate to one skilled in the art the possibility of features that maybe combined in various embodiments to create enhanced transmission andreception systems and methods.

In addition, it should be understood that any figures which highlightthe functionality and advantages, are presented for example purposesonly. The disclosed architecture is sufficiently flexible andconfigurable, such that it may be utilized in ways other than thatshown. For example, the actions listed in any flowchart may bere-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare not familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The Abstract of the Disclosureis not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. 112. Claims that do not expressly include the phrase “means for”or “step for” are not to be interpreted under 35 U.S.C. 112.

What is claimed is:
 1. A method comprising: receiving by a wirelessdevice, an uplink multi-subframe grant for a licensed assisted access(LAA) cell, the uplink multi-subframe grant comprising: radio resourcesof an uplink burst comprising a plurality of consecutive subframes; aphysical uplink shared channel (PUSCH) starting position fieldindicating a PUSCH starting position in a subframe of the plurality ofconsecutive subframes; and a listen-before-talk (LBT) type fieldindicating at least one of a first LBT type or a second LBT type for thesubframe of the plurality of consecutive subframes; determining, atleast based on uplink transmissions by the wireless device in apreceding adjacent subframe to the subframe of the plurality ofconsecutive subframes and a maximum channel occupancy time (MCOT) notexpiring in the subframe of the plurality of consecutive subframes, to:ignore the LBT type field in the uplink grant by not performing an LBTprocedure for the subframe of the plurality of consecutive subframes;and transmit uplink signals in the subframe of the plurality ofconsecutive subframes without performing the LBT procedure for thesubframe of the plurality of consecutive subframes, regardless of theLBT type field indicating the first LBT type or the second LBT type; andtransmitting, via the LAA cell, the uplink signals in the subframe ofthe plurality of consecutive subframes.
 2. The method of claim 1,wherein: the first LBT type is a Category 4 LBT; and the second LBT typeis a Category 2 LBT.
 3. The method of claim 1, wherein the PUSCHstarting position field indicates that PUSCH transmissions in thesubframe start from a beginning of symbol zero.
 4. The method of claim1, wherein the wireless device transmits without a transmission gapbetween the preceding adjacent subframe and the subframe.
 5. The methodof claim 1, wherein the determining to transmit the uplink signals inthe subframe without performing the LBT procedure for the subframe isfurther based on the wireless device transmitting without a transmissiongap between the preceding adjacent subframe and the subframe.
 6. Themethod of claim 1, wherein the determining to transmit the uplinksignals in the subframe without performing the LBT procedure for thesubframe is further based on the PUSCH starting position fieldindicating that PUSCH transmissions in the subframe start from abeginning of symbol zero.
 7. The method of claim 1, wherein the wirelessdevice transmits in a last symbol of the preceding adjacent subframe. 8.The method of claim 1, wherein the determining to transmit the uplinksignals without performing the LBT procedure for the subframe is furtherbased on the wireless device transmitting in a last symbol of thepreceding adjacent subframe.
 9. The method of claim 1, furthercomprising receiving a second uplink grant for the preceding adjacentsubframe.
 10. The method of claim 9, wherein the second uplink grant isone of: a single-subframe uplink grant; or a multi-subframe uplinkgrant.
 11. A wireless device comprising: one or more processors; andmemory storing instructions that, when executed by the one or moreprocessors, cause the wireless device to: receive an uplinkmulti-subframe grant for a licensed assisted access (LAA) cell, theuplink multi-subframe grant comprising: radio resources of an uplinkburst comprising a plurality of consecutive subframes; a physical uplinkshared channel (PUSCH) starting position field indicating a PUSCHstarting position in a subframe of the plurality of consecutivesubframes; and a listen-before-talk (LBT) type field indicating at leastone of a first LBT type or a second LBT type for the subframe of theplurality of consecutive subframes; determine, at least based on uplinktransmissions in a preceding adjacent subframe to the subframe of theplurality of consecutive subframes and a maximum channel occupancy time(MCOT) not expiring in the subframe of the plurality of consecutivesubframes, to: ignore the LBT type field in the uplink grant by notperforming an LBT procedure for the subframe of the plurality ofconsecutive subframes; and transmit uplink signals in the subframe ofthe plurality of consecutive subframes without performing the LBTprocedure for the subframe of the plurality of consecutive subframes,regardless of the LBT type field indicating the first LBT type or thesecond LBT type; and transmit, via the LAA cell, the uplink signals inthe subframe of the plurality of consecutive subframes.
 12. The wirelessdevice of claim 11, wherein the wireless device transmits without atransmission gap between the preceding adjacent subframe and thesubframe.
 13. The wireless device of claim 11, wherein the instructions,when executed by the one or more processors, further cause the wirelessdevice to determine to transmit the uplink signals in the subframewithout performing the LBT procedure for the subframe based on thewireless device transmitting without a transmission gap between thepreceding adjacent subframe and the subframe.
 14. The wireless device ofclaim 11, wherein the instructions, when executed by the one or moreprocessors, further cause the wireless device to determine to transmitthe uplink signals in the subframe without performing the LBT procedurefor the subframe based on the PUSCH starting position field indicatingthat PUSCH transmissions in the subframe start from a beginning ofsymbol zero.
 15. The wireless device of claim 11, wherein the wirelessdevice transmits in a last symbol of the preceding adjacent subframe.16. The wireless device of claim 11, wherein the instructions, whenexecuted by the one or more processors, further cause the wirelessdevice to determine to transmit the uplink signals without performingthe LBT procedure for the subframe based on the wireless devicetransmitting in a last symbol of the preceding adjacent subframe. 17.The wireless device of claim 11, further comprising receiving at leastone message comprising configuration parameters of the LAA cell.
 18. Thewireless device of claim 11, wherein the instructions, when executed bythe one or more processors, further cause the wireless device to receivea second uplink grant for the preceding adjacent subframe.
 19. Thewireless device of claim 11, wherein the uplink grant further comprisesa PUSCH ending symbol field indicating whether the PUSCH is transmittedin a last symbol of the subframe.
 20. The wireless device of claim 18,wherein the second uplink grant is one of: a single-subframe uplinkgrant; or multi-subframe uplink grant.